This is a good example of the sort of intentional naivete of open source developers. Most people see "free" and think "gratis", not "libre". You can argue "that's not what it means" until you're blue in the face. It doesn't matter when that's how most people treat it.
Yes we should. Though I kinda find the "slavery" comment a bit hyperbole, I don't think there are many people who are forced under duress to work on OSS.
this seems like an odd choice of phrasing. those two things are not orthagonal.